The present invention relates to a spiral wound type membrane module or used in a membrane separation device such as a microfiltration device, an ultrafiltration device, or a reverse osmosis membrane separation device.
A spiral wound type membrane module has membranes which are wound around a water collection pipe.
FIG. 7 shows a conventional spiral wound type membrane module wherein a plurality of envelope-like membranes 2 are wound around a water collection pipe 1 with mesh spacers 3 therebetween to form a roll 5. The pipe 1 is provided with slits or openings communicating between the outside and the inside of the pipe 1.
Each membrane 2 in an envelop shape has an inside which communicates with the inside of the pipe 1. The envelope-like membrane 2 contains an inside spacer 4 therein such as a mesh-like spacer, so that the inside of the membrane 2 constitutes a permeated water channel.
The roll 5 of the membranes 2 is provided with unti-telescopers 6,7 at its both ends and brine seals 8 are fitted around the unti-telescopers 6,7.
Feed water flows from the front end of the roll 5 into each feed water channel between the membranes 2 and further flows in the longitudinal direction of the roll 5. Concentrate water flows out of the rear end of the roll 5. During the water flows in the feed water channels, the water permeates through the membranes 2 and flows into the pipe 1 and is taken out from the end of the pipe 1 as permeated water.
The conventional spiral element described above requires the water collection pipe 1 having large diameter for large amount of water flowing therein, whereby the diameter of the spiral wound type membrane element becomes large.